


Muscle Groups

by colieb2183



Category: Voltron: Legendary Defender
Genre: Anal Sex, Dirty Talk, Friends With Benefits, GlitterBeefs, Howdy AU, I apologize for nothing, Kinkashi, Light Dom/sub, M/M, Muscles, Orgasm Delay/Denial, Plot What Plot/Porn Without Plot, Rimming, Sex Toys, This is pure filth, Yeehaw AU, kind of
Language: English
Status: Completed
Published: 2018-08-27
Updated: 2018-08-27
Packaged: 2019-07-03 03:03:12
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,853
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/15809994
Author URL: https://archiveofourown.org/users/colieb2183/pseuds/colieb2183
Summary: Shiro is being good for once and helping Kinkade study. He's such a good friend.





	Muscle Groups

**Author's Note:**

  * For [buffshiro](https://archiveofourown.org/users/buffshiro/gifts).



> This story is set in the Howdy!AU universe technically, although it could be read as part of the Yeehau!AU. Keith is not mentioned.
> 
> I do not have a medical degree and definitely did not take anatomy in school. All information was gleaned through good ole internet searching.
> 
> Thank you so much to @buffshiro I have never published fanfic before and you have inspired me so much with this ship, I couldn't help it. I hope you love this.

 “Three types of muscular tissues.”

“Cardiac, Skeletal, Smooth.”

“Yup. List three histological or physiological defining characteristics of skeletal muscle.”

“Voluntary…. Multinucleate… aaand…….. Fuck.”

Shiro glances up from the flash cards in his hand to see Kinkade hunched forward, head in his hands. He growls in frustration. “I swear I know this one… I got it right last time.”

“You did,” Shiro agrees, stretching his back and readjusting his feet in Kinkade’s lap. After a few seconds of silence he suggests, “Maybe you should take a break. We’ve been at this for almost two hours.”

Kinkade glances derisively at Shiro between his fingers. “Stop. You’re not sucking my dick and calling that a ‘break’. I have this exam in two days.”

Shiro pouts, “I still think that strip rewards for correct answers was a good idea.”

Kinkade grunts, drops his arms, and sprawls against the back of his couch, “You’re the worst. Why are we friends?

“Because I have a great ass,” Shiro winks at his friend.

Kinkade smirks at the ceiling, “True….”

A dark look passes across his face before he gently pushes Shiro’s legs off his lap and stands to take the leftover orange chicken to his tiny galley kitchen off the living room.

Shiro sighs, resigned to helping his best friend study rather than seeing just how many additional inches of that cock he could fit down his throat. He was so close to fitting every single glorious inch the last time that he thinks about it every time he sees Kinkade thrust those sinful hips on stage. He rearranges his own half-hard length in his basketball shorts, shuffling through the remaining flashcards. “Do you want me to go on to the next one?” he calls out.

“No….,” Kinkade’s voice drifts back from the kitchen in between dishes clinking, “Just let me think for a minute.”

Shiro sighs again and reaches out to grab an abandoned fortune cookie next to a stack of thick textbooks on the table. “Just make sure you actually eat those leftovers this time. I can’t keep coming over here as your personal reminder that food is necessary.” He nibbles at the cookie, discarding the paper fortune and wrapper on the table.

“Yes, you fucking mother hen. Don’t lie to me. I know your food comes with ulterior motives.”

Grinning widely, Shiro sits up and drapes his torso over the back of the couch, “It’s not my fault that you retreat into your dark cave and forget that humans need to eat. I need my beefy best friend well fed so he can lift me up and fuck me silly. Muscles need fuel. C’mon Ryan, you should know this, you’re supposedly going to be a doctor.” He shakes his head in mock disapproval. “Maybe you’re right. Less fucking. More studying.”

“Can you say that again so I can record it and play it back to you the next time you’re scratching at my door like a damn cat in heat?” Kinkade snipes back, sticking his head around the corner and rolling his eyes, “And the missing answer is striated.” He raises his eyebrow flirtatiously and disappears back into the kitchen.

Shiro barks out a laugh and flops back down to the lumpy couch cushion. “Correctomundo sir. Onto the next.”

He hears footsteps and Kinkade’s broad shadow appears looming over him. “We’ve been through these flashcards twice now. I think I should move on to study muscle identification.”

Shiro looks up, surprised. “Oh, ok…do you have like a worksheet for that or something?”

A predatory look spreads slowly across Kinkade’s face. “Something like that.” He leans down and presses his lips to Shiro’s. Shiro makes a muffled noise of surprise before melting into it. He enthusiastically deepens the kiss, curling his tongue around Kinkade’s, sharing the slightly stale sweetness leftover from the fortune cookie. Kinkade’s long fingers drag through Shiro’s silver locks – the black roots just starting to peek through. Shiro moans. God, Kinkade was a damn good kisser.

Kinkade bites Shiro’s lip and then pulls away entirely. His gaze sweeps hungrily across Shiro’s dazed expression and he turns to walk down the short hallway to his bedroom.

Shiro is left panting and painfully hard. After a second of bemusement, he scrambles to his feet, flashcards scattering forgotten to the floor.

When he reaches the bedroom, he sees Kinkade standing shirtless in front of his dresser with his back to the door. “Strip.” The order is made bluntly, clearly expecting immediate obedience. Shiro hurriedly yanks his black tee over his head and drops it to the floor. His shorts follow quickly behind.

Kinkade turns around, and with a carefully blank face, gestures to the bed in the corner of the sparsely decorated room. The mattress sat directly on top of the box frame. The last time Shiro was over, they accidentally put a hole in the wall with the edge of the metal bedframe. They laughed themselves silly while they patched it the next day, each of them covered in repair putty. It was decidedly safer to forego a frame to avoid losing his security deposit, so Kinkade had discarded it.

Shiro lies prone on his stomach, skin prickling in anticipation. Kinkade closes the drawer of his dresser and sets something on the floor at the end of the bed. Shiro sighs in happiness. He’s such a good friend. He came over and fed Kinkade, helped him study without begging, and he was still going to get dicked down good and hard. His internal self-congratulation is interrupted by Kinkade tapping his fingers on the outside of Shiro’s thigh.

Shiro knows the signal well. He turns his shoulder and flips to his back, linking his fingers behind his head. His cock bobs and slaps back against his toned stomach. Gleaming, Kinkade’s eyes fixate on the hardness between his legs. Shiro breathes out sharply, arching his back and spreading his thighs. Beckoning.

The gleam in Kinkade’s eyes intensifies. “Oh no,” he purrs, “you haven’t heard the rules yet.” Shiro shivers from head to toe. He loves it when Kinkade plays these kinds of games. “Tell me,” he whispers in return. His body undulates in mimicry of Kinkade’s favorite pole routine. The last time Shiro did this routine, Kinkade had stalked him back to the green room and slammed him against the locked door. Shiro had to call in for three days straight. It was worth it.

Kinkade sinuously creeps forward, kneeling on the mattress, “You do not get to touch.” Shiro nods in understanding. “You do not get to touch me. You do not get to touch yourself. You come when I say that you can.” Shiro nods again, a little more frantically. “Good boy.” His cock twitches at the praise. “You know how to make it stop.”

He does. He and Ryan had discussed this extensively in the past. He also knows that it is always worth his while to hold out until the end, but he trusts that Ryan will stop the moment he lets that word escape from his lips.

“I thought you needed to study.”

“I _am_ studying.” Kinkade’s teeth gleam as he holds up a ballpoint pen and leans down to drag it across Shiro’s shin.

Shiro’s jaw drops open. He has to be kidding. He absolutely HAS to be kidding. Kinkade finishes outlining the muscles on his left shin, and starts to write the muscle names in his neat cramped handwriting.

_Fibularis brevis, Tibialis anterior…_

The slow exploration continues up Shiro’s leg, each muscle outlined and labeled carefully. Shiro lays obediently still, rock hard and feeling increasingly frustrated. Suddenly, Kinkade’s tongue swirls around Shiro’s swollen cockhead. Shiro nearly screams in surprise. He whips his head forward, and stares wide eyed at Kinkade. Kinkade hums in pleasure, and takes Shiro down to the root before pulling back off and leaving with one last flick of his tongue. He continues down the opposite leg. Shiro’s head drops back to the pillow with a groan.

How many muscles are there in the human body? Shiro has no idea as Kinkade makes slow progress up his abdomen, sucking on each sensitive spot as he goes. The build-up is so slow, and Shiro’s cock is starting to throb.

Kinkade is straddling his hips and detailing the muscles in his shoulder when a desperate whine finally escapes his lips.

Kinkade smiles against his collarbone and grinds down slowly, trapping his cock between them. Shiro’s head tips back baring his neck, and Kinkade nips him lightly. The fabric of Kinkade’s university sweats is almost too much stimulation and tears prick at the corners of his eyes.

_Trapezius, Deltoid, Biceps brachii…_

Once he finishes both arms, Kinkade hooks his arms under Shiro and flips him over to his stomach. Shiro cries out as his sensitive shaft brushes against the sheets. Kinkade yanks him up to his knees.

Shiro can hear the pop of a cap behind him and pleads for the first time, “Please Ryan, please, please touch me. Pleaaasee.”

Instead of a finger, he feels something cool and flexile touch his exposed hole. He tenses in surprise and pushes himself to his elbows so he can look over his shoulder. What he sees nearly takes his breath away. Kinkade must have gotten a new toy since the last time they nearly broke through the wall into the next apartment. He is holding a bright purple beaded plug and staring hungrily at where it’s disappearing inside Shiro’s body.

It takes a few minutes for Kinkade to work it inside of him. Shiro tries his hardest to hold still, gasping as he feels each increasing bead size stretch his passage wider. A long wail leaves his lips when he feels the base of the plug nudge against his skin. An even higher pitched wail leaves his lips when the plug starts to vibrate.

Well fuck. Kinkade is full of surprises tonight.

_Triceps brachii, Anconeus…_

The soft scrape of the ballpoint across his skin is followed by the drag of an open mouth, the occasional graze of teeth and swipe of tongue – each touch tantalizingly and infuriatingly light. Enough to keep Shiro’s nerves on fire.  Never enough to send him over the edge. His cock slowly drips precum to the sheets, but he’s been given precise instructions that he’s not to touch. A command that his body is screaming at him to disobey.

_Adductor magnus, Sartorius, Plantar, Soleus…_

Kinkade makes his way slowly down the back of Shiro’s right leg, smoothing his free hand over Shiro’s ass as he goes. Shiro is shaking. His muscles tensing and jumping in reaction to the decadently slow exploration.

Finishing with his right leg, Kinkade moves from his side to kneel directly between his legs.  Shiro spread them wide with a whine, wanton and shameless. The hand on his ass moves to the base of the purple silicone plug nestled deep within Shiro, pushing on it gently with his thumb. Slowly grinding it in circles.

Shiro’s voice breaks on a scream and his hips thrust back hard. Desperate. Pleading. He feels a huff of laughter against his hole followed by the dirtiest swipe of tongue around the plug. It has him keening, head dropping to the pillow, and pushing back for more.

“Now, now, you want me to fuck you, don’t you?”

“Yes, yes, _please_ Ryan,” Shiro nearly cried.

“Then stay still, or I will tie you up, paint you with my cum and leave you sit until I finish studying for this exam.”

The groan Shiro let out at that visual image doesn’t even sound human. Satisfied, Kinkade moves away from his ass and starts down the opposite leg.

_Biceps Femoris, Gastrocnemius, Peroneus longis.._

He slips his right thumb in alongside the plug as he continues “studying”. Shiro struggles to hold his hips still, shuddering, “Oh my fucking _god_ , Ryan, _please.”_

“You know what to say if you really need it to stop.”

Shiro nearly screams in frustration. STOP? No, he doesn’t need it to stop. He knows this game and knows Kinkade will make him come so hard the world will shatter as long as he can play along. He bites his lip, tears spilling onto his cheeks as Kinkade’s thumb moves deeper, sending shockwaves throughout his body.

He whimpers softly. The beads on the plug are now pressing directly on his prostate and nudge it a little more with every movement of Kinkade’s thumb. Again. And again.

“Good boy,” Kinkade purred, pausing halfway down Shiro’s calf to move back up and slide his tongue alongside his thumb and the plug. It’s a fucking dirty move and Kinkade knows it. Shiro’s breath freezes in his throat. Another strand of precum drips off his twitching cock to join the pool gathering on the sheets. Ryan is going to wreck him.

After another wriggle of his tongue, Kinkade pulls back and replaces his thumb with two fingers. Shiro wails, high and broken. He drops from his elbows down to his chest, face buried in the pillow, desperation flooding through him.  He doesn’t know how much more of this he can handle, but he doesn’t want to lose the game. Kinkade’s fingers are moving with purpose now, scissoring and spreading.

Shiro can feel his orgasm building deep in his core. He gropes backwards, grabbing Kinkade’s wrist in warning. “ _Ryan,_ ” he groans.

Kinkade pulls out his fingers along with the plug leaving Shiro gasping, his hole gaping. Shiro sobs, bereft and clenching around nothing. He can feel Kinkade get off the bed and pull off his sweatpants and reach down to the floor for the condom he left there earlier. Finally ,FINALLY, he was going to get what he wanted, what he needed. It had been over an hour with Kinkade skillfully pushing him closer and closer and never allowing him more than the briefest scorch of heat. Shiro’s skin is crawling with the need to be fucked 

Climbing back onto the end of the bed, Kinkade drags his hands all the way up both of Shiro’s legs to his waist. He leans his weight over Shiro , fingers dipping low to the sheets to scoop up the precum Shiro had been leaking. He presses himself tight to Shiro’s back and brings his fingers up to Shiro’s mouth, stuffing them inside. Shiro moans and swirls his tongue around Kinkade’s fingers, tasting himself, desperately grinding against the hardness nestled between his cheeks.

“How badly do you want my cock, huh? All that whining and writhing around on my bed like the slut that you are,” he taunts, scraping his teeth against Shiro’s ear. Shiro keens.  “Think you can make it until the end? Can you earn it?”

Shiro moans around Kinkade’s fingers and nods his head desperately.

He can almost feel Kinkade’s smirk against his neck before he lifts off of Shiro. Shiro twists his head to look back and make eye contact as Kinkade smacks the swollen head of his cock a few times against Shiro’s stretched hole. Shiro gasps, his eyes slamming shut and concentrates on not ripping Kinkade’s sheets with his prosthetic while arching back against Kinkade. “Holy SHIT.”

The thick head presses past the initial ring of muscle, and Shiro inhales sharply against the stretch. Kinkade slowly fucks into Shiro, inch by inch. Searing heat zings up Shiro’s spine as he struggles to take him all in. _Fuck_ , Kinkade was big _._ The slightest huff of breath fans against the back of his neck as Kinkade finally bottoms out. Shiro lets out a strangled groan. He reaches both hands out and braces himself against the wall, anticipating a brutal, pounding fuck. Kinkade doesn’t move. He stays lodged so deep Shiro swears he can taste it in his throat.

Shiro breath hisses between his teeth as he squirms, begging with his body for more. He feels a finger drag lightly across his back, tracing the dips and the valleys between the bunched muscles of his shoulder blades. Kinkade leans forward and swipes his tongue against the shell of Shiro’s ear. “Wait,” he whispers darkly.

Shiro’s breath explodes out of him in a whine as Kinkade leans back again and grabs his pen from where it laid discarded next to Shiro’s hip.

_Trapezius, Deltoid, Infraspinatus…_

Fuck. Shiro had completely forgotten about the muscles in his back. Gasping for breath, he suppresses every instinct within him to give up and start fucking himself back on Kinkade’s dick.

_Latissimus dorsi, Thoracolumbar fascia, External oblique…_

He’s halfway down Shiro’s side when he starts to slowly grind himself into Shiro. Shiro cries out sharply and inhales through his nose to try and control himself. His entire body shakes with the effort.

_Internal oblique, Gluteus medius…_

Kinkade pulls all the way out to the tip, agonizingly slow, and then just as slowly thrusts back in until he bottoms out again. A deep sigh of satisfaction escapes his mouth. Whimpers and moans are endlessly dropping off Shiro’s lips. He’s trying so hard not to move. Not to grind. Not to flip them over and ride Kinkade to completion. Trying to wait.

_Splenius capitis, Splenius cervicis…_

So close… he loves this game just as much as he hates it…

_Rhomboid major, Erector spinae, serratus posterior inferior…_

Kinkade pauses and leans forward again. Shiro groans as he feels the weight against his back. Kinkade digs his fingers deep into Shiro’s hips and rests his chin on Shiro’s shoulder. He pulls out briefly and then slams back in. Shiro screams into the pillow. Kinkade hums and bites down on Shiro’s shoulder, “Only one left, do you know what it is?”

Shiro does. Kinkade saved his favorite for last. “ _Yes_ ,” Shiro breathes.

Satisfied, Kinkade hums once more and pulls Shiro back up to his hands as he kneels behind him. He writes the last muscle on Shiro’s body…

_Gluteus maximus…_

He throws the pen to the floor and snaps his hips hard. Shiro howls, bracing his hands against the wall again to take the impact. Kinkade swears and does it again. Shiro’s head hangs low between his shoulders, mouth agape, chest heaving. “Yesss _._ Oh my god, plea – Ah!”

He yelps as Kinkade slaps his ass and then starts pistoning in and out of him. “You know how many people at the club wish they could be here right now?” Shiro moans. “Wish that they could sink their cock into this thick ass bubble butt?”

He can feel himself getting closer to the edge. He can hear himself getting louder and louder as Kinkade fucks him towards oblivion.

Mid scream, Kinkade pulls him up to his knees and sits back with Shiro straddling his lap, slapping a hand over Shiro’s mouth. Shiro reaches behind his head to tangle his fingers in Kinkaid’s dreadlocks, bouncing his hips up and down obscenely. Kinkade lets out a deep groan when Shiro pulls hard on a few dreads.

Dimly, he notices that Kinkade is reaching down towards his front. So close, he’s so fucking close. Just a little bit more. He feels a hand wrap around his neglected cock and he drops his head back on Kinkade’s shoulder. “Aaaah… oh my god, yesss.” A loop of latex wraps around the base of his length and tightens.

Shiro looks down in shock. Kinkade had not only purchased a new plug, he also had apparently invested in a lasso style cock ring. “No, Ryan please, please let me come, _please,_ ” he pleads hoarsely.

Kinkade chuckles in his ear, “Not yet, just a little while longer. You’ve earned it.” Tears are streaming down Shiro’s face as Kinkade pushes him face first back into the mattress and holds him down by the back of the neck. Kinkade is growling through clenched teeth as he continues his punishing pace. “Just look at you. Always walking around and tempting me. I can never get anything done when you’re here. All I can think of is bending you over the arm of my sofa and fucking you until you can’t walk.”

Shiro is incoherent. The pressure on the back of his neck feels exquisitely wicked. His entire body is pulled taut, drool smearing from his lips on the pillowcase, his cock starting to turn an angry red.

“Especially when you’re not begging for my dick. It makes me want to destroy. You. Even. More.” He punctuates each word with savage thrusts that scatter sparks across Shiro’s vision. He’s going to pass out. “GOD, do you want to come for me, huh? I wanna feel your ass squeezing my dick as I come.” Shiro’s voice is almost non-existent as he screams and nods so hard he thinks he’s going to give himself whiplash.

He feels Kinkade fumbling with the cockring and then he finally tugs the ball down the silicone releasing Shiro’s cock. His entire world whites out. The fire that had been building all night ravages through him, rendering him unable to speak or move. He barely registers Kinkade swearing behind him, thrusting a few more times before stilling deep inside. He falls to his hands, hovering and panting above Shiro’s back. Unable to hold himself up anymore, Shiro collapses to his front, directly in his own puddle of cum. The world feels fuzzy and out of focus as he shakes uncontrollably.

Kinkade is dripping sweat all over his back as he leans down to press a sloppy open mouth kiss to Shiro’s shoulder. Shiro jerks away from the contact. His skin is buzzing and any contact feels like a firebrand.

He’s dimly aware of Kinkade crawling off the mattress and leaving the room.

Shiro doesn’t move, his body slowly coming down from its high, randomly convulsing. When his breathing finally returns to normal and the convulsions stop, he cracks an eye open to see Kinkade crouching down next to his head, affection glinting in his dark grey eyes. “C’mon let’s get you in bed.”

He gently helps Shiro sit up and drink a bottle of Gatorade. All he has left is the red flavor, which he knows Shiro hates, but Shiro gulps it down anyway. While Shiro is finishing off the Gatorade, Kinkade strips the bed and throws down an old worn comforter.

When Shiro sleepily raises an eyebrow at him, Kinkade shrugs and mumbles, “This is easier.” Shiro huffs a weak laugh and allows Kinkade to guide his body back down on the bed and run a damp washcloth down his stomach to clean off most of the drying cum. He carefully avoids touching Shiro’s oversensitive skin too much.

Shiro expects him to flop down on the bed and immediately pass out, but Kinkade surprises him by reaching out towards Shiro and pulling him close. Too tired to question it, he allows Kinkade to tuck himself behind Shiro, snaking his arm around to secure them tightly together.

And then the doorbell rings.

Kinkade swears, “Damnit Shiro, we need to figure out a way to keep you quieter. If this is the police again, I can’t keep affording disturbance of the peace tickets.

Shiro chuckles quietly as Kinkade stumbles out of bed, tugging on Shiro’s discarded shorts to answer the door.

 

**Author's Note:**

> Feedback is welcome and encouraged! I haven't written anything since college, so I am admittedly a little rusty. I can fix any weird grammar mistakes I missed when editing. Thank you for reading!
> 
> Apparently there was something in the air, because The_Tangled_Bed_of_Roses posted her fic at almost exactly the same time as I did. Shiro being needy, Ryan trying to study, kink galore, everything you could ask for. Check it out, but make sure you pay attention to the tags cuz hooooo boy it's one hell of a ride. [Study Break](https://archiveofourown.org/works/15809841/)


End file.
